I know it seems like a great happy accident. But I actually know that unit really well, and I've seen that frost before. So when I saw it develop this last time, I went ahead and decided to leave it and record it.
It's best to pull it into a vacuum every time when you're pumping down. The easy way to do it is to attach a core removal tool to the valve, pump down into a vacuum, then refill with nitrogen to prevent moisture from entering the system when you open the line-set. Not only will your charge be accurate when you release it, you'll also be already set-up to flow nitrogen while you're brazing. Botta-bing botta-boom
Agreed. But best practices and what lazy asses do in the field are two very different things if you haven't noticed. But I agree with you one hundred percent.
Those are actually crappy gauges. I used them because it's what the students had that year. So, not at all. The hoses are not vacuum rated. If you want to do it right, Imperial, Hilmor, and Fieldpiece make good manifolds. And then sub out the standard houses for black vacuum rated hoses. The best way is no manifold from my other video. At least, it's best for pulling a vacuum.